The present invention relate to an electrical device connection terminal, and more particularly to an electrical device connection terminal having a socket function for electrically connecting electrical devices, such as relays and timers, to external circuits via lead wires.
A conventional electrical device connection terminal is disclosed in DT-OS (DE 19629563 A1), for example.
More specifically, in the electrical device connection terminal shown in FIG. 4 of the above-mentioned publication, for example, a clamp spring installed on one side of one end of a lead fitting is mounted in a clamp spring accommodation portion provided in a base. Furthermore, in the electrical device connection terminal, a lead wire is inserted into the connection hole in the clamp spring by operating the clamp spring using a screwdriver or the like. Hence, the lead wire is held between the lead fitting and the clamp spring by the force of the clamp spring, thereby establishing electrical connection. Because of this configuration, if the lead wire is forcibly pulled out from the clamp spring, a part of the lead wire may be broken off, and lead wire chips may drop.
In particular, in the above-mentioned electrical device connection terminal, the lead fitting is mounted in the base afterwards. Hence, a gap may occur between the base and the lead fitting owing to variations in the accuracy of components and the accuracy of assembly. The lead wire chips are apt to get into the gap. In addition, if vibration and external forces are applied to the base, the base may be deformed elastically, whereby the gap may become wider, and the lead wire chips having built up may drop downward and may build up further. As a result, a downwardly disposed lead fitting may be short-circuited to another upwardly disposed lead fitting, thereby being in danger of causing improper insulation.
Furthermore, in a general electrical device connection terminal, its base is fitted into its case so as to be covered. Hence, it is inevitable that a gap occurs between the outside face of the base and the inside face of the case. Therefore, lead wire chips may drop through the gap and build up. As a result, a downwardly disposed lead fitting may be short-circuited to another upwardly disposed lead fitting, thereby being in danger of causing improper insulation.
In consideration of the above-mentioned problems, the present invention is intended to provide an electrical device connection terminal capable of preventing improper insulation owing to lead wire chips having been broken off lead wires and then dropped and built up.
An embodiment of the present invention is an electrical device connection terminal wherein clamp spring accommodation portions and lead wire holding portions are formed directly below operation rod insertion holes and lead wire insertion holes formed in parallel on the top face of a base, respectively; nearly L-shaped grooves communicating with the clamp spring accommodation portions and the lead wire holding portions are provided on the side face of the base; nearly L-shaped lead fittings provided with a clamp spring on one side of the upper end of each lead fitting are press-fitted into the L-shaped grooves sideways; by inserting lead wires inserted through the lead wire insertion holes into the connection holes in the clamp springs while operating the clamp springs with an operation rod inserted into each of the operation rod insertion holes, each of the lead wires is held between the lead fitting and the clamp spring by the spring force of the clamp spring to establish electrical connection, the electrical device connection terminal is characterized in that a side wall for separating the lead wire holding portion from the lead fitting is projected on the bottom face fringe of the lead wire holding portion so as to be adjacent to one side of the lead fitting.
Hence, in accordance with the present invention, even if a part of a lead wire is broken and lead wire chips drop, the lead wire chips build up inside the lead wire holding portion separated by the side wall. For this reason, even if a gap occurs between the lead fitting and the base, the lead wire chips do not drop through the gap, thereby preventing improper insulation owing to the dropping and build up of the lead wire chips.
Another embodiment of the present invention may be an electrical device connection terminal wherein clamp spring accommodation portions and lead wire holding portions are formed directly below operation rod insertion holes and lead wire insertion holes formed in parallel on the top face of a base, respectively; nearly L-shaped grooves communicating with the clamp spring accommodation portions and the lead wire holding portions are provided on the side face of the base; nearly L-shaped lead fittings provided with a clamp spring on one side of the upper end of each lead fitting are press-fitted into the L-shaped grooves sideways; by inserting lead wires inserted through the lead wire insertion holes into the connection holes in the clamp springs while operating the clamp springs with an operation rod inserted into each of the operation rod insertion holes, each of the lead wires is held between the lead fitting and the clamp spring by the spring force of the clamp spring to establish electrical connection, the electrical device connection terminal is characterized in that projection portions are disposed on the inside faces of a case to be fitted with the base so as to be fitted into and block the side openings of the lead wire holding portions formed in the base.
Hence, in accordance with the present invention, lead wire chips do not drop from the side openings of the lead wire holding portions along the inside faces of the case, thereby preventing improper insulation owing to the drop and buildup of the lead wire chips.
Still another embodiment of the present invention may be an electrical device connection terminal wherein projection portions are formed on the inside faces of the case to be fitted with the base so as to be fitted into and block the side openings of the lead wire holding portions formed in the base, and the projection portions are fitted into the upper ends of the side walls of the lead wire holding portions so as to support the side walls.
In accordance with the present invention, the projection portions formed on the case to block the side openings of the lead wire holding portions are fitted into the upper ends of the side walls forming the lead wire holding portions so as to support the side walls. Hence, the side walls are reinforced and strengthened.
Still another embodiment of the present invention may be an electrical device connection terminal wherein clamp spring accommodation portions and lead wire holding portions are formed directly below operation rod insertion holes and lead wire insertion holes formed in parallel on the top face of a base, respectively; nearly L-shaped grooves communicating with the clamp spring accommodation portions and the lead wire holding portions are provided on the side face of the base; nearly L-shaped lead fittings provided with a clamp spring on one side of the upper end of each lead fitting are press-fitted into the L-shaped grooves sideways; by inserting lead wires inserted through the lead wire insertion holes into the connection holes in the clamp springs while operating the clamp springs with an operation rod inserted into each of the operation rod insertion holes, each of the lead wires is held between the lead fitting and the clamp spring by the spring force of the clamp spring to establish electrical connection, the electrical device connection terminal is characterized in that the lead wire holding portion is enclosed with side walls each having a flat and nearly square shape and projecting along the bottom face fringe of the lead wire holding portion.
In accordance with the present invention, the lead wire holding portion disposed in the base and being capable of accommodating lead wire chips is enclosed with the side walls in four directions. For this reason, lead wire chips do not drop along the side face of the lead fitting and the inside faces of the case, thereby preventing improper insulation. Furthermore, it is not necessary to form projection portions on the inside faces of the case, whereby the design of the case is simplified.
Still another embodiment of the present invention may be an electrical device connection terminal wherein assembly-use hold holes formed near the upper end of the lead fitting are blocked by the side wall projecting along the bottom face fringe of the lead wire holding portion.
In accordance with the present invention, the assembly-use hold holes are blocked by the side wall enclosing the lead wire holding portion. For this reason, lead wire chips do not drop through the hold holes to the clamp spring accommodation portion adjacent to the lead fitting. Hence, improper insulation can be prevented more securely.